How to create a created_by field in django rest framework model?

Question

I want to create a created_by field in django rest framework model.

It should contain, user_id of currently logged in user and it should be such that I need not send it during POST request in JSON format, it should be taken from request itself, how can I implement it using django rest framework serializer.

models.py file:

class Company(models.Model):
    """Company model for information about company."""

    created_by = models.ForeignKey(User, null= True, blank= True, on_delete=models.CASCADE)
    company_name = models.CharField(max_length=100)

serializers.py file:

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')

v1.py file:

class CompanyList(APIView):
"""Get and post companies data."""

    def get(self, request, format=None):
        """Get companies data.."""
        companies = Company.objects.all()
        serialized_companies = CompanySerializer(companies, many=True)
        return Response(serialized_companies.data)

    def post(self, request, format=None):
        """Post companies data."""
        serializer = CompanySerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Answer 1

Method-1: Using CurrentUserDefault() option

You can pass default parameter in created_by field as serializers.CurrentUserDefault() which will set its value as the current user.

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')
        extra_kwargs = {'created_by': {'default': serializers.CurrentUserDefault()}}

Method-2: Passing user in serializer.save()

You can set the field created_by as read_only and then pass request.user to serializer.save().

serializers.py

class CompanySerializer(serializers.ModelSerializer):
"""Serializer for companies."""

    class Meta:
        model = Company
        fields = ('id', 'created_by', 'company_name')
        extra_kwargs = {'created_by': {'read_only':True}}

v1.py

class CompanyList(APIView):
"""Get and post companies data."""

    def post(self, request, format=None):
        """Post companies data."""
        serializer = CompanySerializer(data=request.data)
        if serializer.is_valid():
            serializer.save(created_by=request.user) # pass current user
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Answer 2

You can just use serializers.CurrentUserDefault() as default for the created_by field in the CompanySerializer and make that field read_only=True.

See the docs here.

Answer 3

Try this solution

models.py file

class Student(models.Model):
    middel_name = models.CharField(max_length=100)
    user = models.OneToOneField(User)

here it's my serializer file

class GetStudentUserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('id','username', 'email', 'first_name', 'last_name')

class GetStudentSerializer(serializers.ModelSerializer):
    user = GetStudentUserSerializer('user.username')
    class Meta:
        model = Student
        fields = ('id','middel_name','user')
        depth = 1

    def create(self, validated_data):
        print "hello"
        student_data = validated_data.pop('student', None)
        user = super(GetStudentSerializer, self).create(validated_data)
        self.create_or_update_student(user, student_data)
        return user

    def update(self, instance, validated_data):
        student_data = validated_data.pop('student', None)
        self.create_or_update_student(instance, student_data)
        return super(GetStudentSerializer, self).update(instance, student_data)

    def create_or_update_student(self, user, student_data):
        student, created = Student.objects.get_or_create(user=user, defaults=student_data)
        if not created and student_data is not None:
        super(GetStudentSerializer, self).update(instance, student_data)